<template>

  <div class="app-container">

    <h2 style="text-align: center;">发布新课程</h2>

    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

    <el-form label-width="120px">

      <el-form-item label="课程标题">
        <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
      </el-form-item>

      <!-- 所属分类 TODO -->
      <el-form-item label="课程分类">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类" @change="subjectLevelOneChanged">

          <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>

        </el-select>

        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"/>
        </el-select>
      </el-form-item>


      <!-- 课程讲师 TODO -->
      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select
          v-model="courseInfo.teacherId"
          placeholder="请选择">

          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"/>

        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
      </el-form-item>

      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description"/>
      </el-form-item>



      <!-- 课程封面 TODO -->
      <!-- 课程封面-->
      <el-form-item label="课程封面">

        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API+'/eduoss/file'"
          class="avatar-uploader">
          <img :src="courseInfo.cover">
        </el-upload>

      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
      </el-form-item>

      <el-form-item>
        <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce' //引入组件
export default {

  //声明组件
  components: {Tinymce},

  data() {
    return {
      saveBtnDisabled:false,
      courseInfo:{
        title: '',
        subjectId: '',//二级分类id
        subjectParentId:'',//一级分类id
        teacherId: '',
        lessonNum: 0,
        description: '',
        cover: '/static/01.jpg',
        price: 0
      },
      courseId: '',
      BASE_API: process.env.BASE_API, // 接口API地址
      teacherList:[],//封装所有的讲师
      subjectOneList:[],//一级分类
      subjectTwoList:[]//二级分类
    }
  },
  created() {

    //获取路由id值
    if(this.$route.params && this.$route.params.id) {
      this.courseId = this.$route.params.id
      //调用根据id查询课程的方法
      this.getcourseInfo()
    } else {
      //初始化所有讲师
      this.getListTeacher()

      //初始化一级分类
      this.getOneSubject()
    }


  },
  methods:{

    //根据课程id查询课程信息
    getcourseInfo(){
      course.getCourseInfo(this.courseId)
        .then(response => {
          this.courseInfo = response.data.courseInfo

          //1.查询所有的分类，包含一级和二级
          subject.findAllSubject()
            .then(response => {
              debugger
              //2. 获取所有一级分类
              this.subjectOneList = response.data.items;
              //3. 把所有的一级分类数组进行遍历，比较当前courseInfo里面的一级id和所有的一级分类id
              for(var i =0 ; i < this.subjectOneList.length ;i++){

                //获取每个一级分类
                var oneSubject = this.subjectOneList[i];
                //比较当前courseInfo里面一级分类id和所有的一级分类id
                if(this.courseInfo.subjectParentId === oneSubject.id){
                  //获取一级分类所有的二级分类
                  this.subjectTwoList = oneSubject.children;
                  console.log(this.subjectTwoList)
                }
              }

            })

          //初始化所有讲师
          this.getListTeacher()
        })
    },

    //上传封面成功调用的方法
    handleAvatarSuccess(res, file) {
      this.courseInfo.cover = res.data.url
    },
    //上传之前调用的方法
    beforeAvatarUpload(file) {
      const isJPG = file.type === 'image/jpeg'
      const isLt2M = file.size / 1024 / 1024 < 2

      if (!isJPG) {
        this.$message.error('上传头像图片只能是 JPG 格式!')
      }
      if (!isLt2M) {
        this.$message.error('上传头像图片大小不能超过 2MB!')
      }
      return isJPG && isLt2M
    },

    // 点击某个一级分类，触发change事件，显示对应的二级分类
    subjectLevelOneChanged(value){
      //value就是一级分类的id

      //遍历所有的分类，包含一级和二级
      for(var i=0 ; i < this.subjectOneList.length; i++){
        //每一个一级分类
        var oneSubject = this.subjectOneList[i]
        //判断： 所有一级分类id 和 点击一级分类id是否一样
        if(value === oneSubject.id){
          //从一级分类获取里面的所有二级分类
          this.subjectTwoList = oneSubject.children

          this.courseInfo.subjectId = ''
        }
      }
    },

    //查询所有的一级分类
    getOneSubject(){
      subject.findAllSubject()
        .then(response => {
          console.log(response.data.items)
          this.subjectOneList = response.data.items;
        })
    },

    // 查询所有的讲师
    getListTeacher(){
      course.getListTeacher()
        .then(response => {
          this.teacherList = response.data.items;
        })
    },

    //添加课程
    addCourse(){
      course.addCourseInfo(this.courseInfo)
        .then(response  => {
          //提示信息
          this.$message({
            type: 'success',
            message: '添加课程信息成功'
          });

          //跳转到第二步
          this.$router.push({path:'/course/chapter/'+response.data.courseId})
        })
    },

    //修改课程
    updateCourse(){
      course.updateCourseInfo(this.courseInfo)
        .then(response => {
          //提示信息
          this.$message({
            type: 'success',
            message: '修改课程信息成功'
          });

          //跳转到第二步
          this.$router.push({path:'/course/chapter/'+this.courseId})
        })
    },

    saveOrUpdate(){
      //判断添加还是修改
      if(!this.courseInfo.id){
        this.addCourse()
      }else{
        this.updateCourse()
      }
    },
  }
}
</script>
</script>
<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>
